A system comprised of a plurality of switches and time reference signals are provided for managing data transfer of data units during a time interval, comprised of a plurality of predefined time frames. During operation a plurality of sources as a Local Time Reference (LTR) signal that collectively constitute the equivalent of a common time reference (CTR) signal. The time reference signals are coupled to each of the switches, such that there is predefined time frames for transfer into and out from each of the respective switches responsive to the time reference signals.